1. Field of the Invention
The generation of electrical current with particular reference to improvements in means for providing useful application of the energy which normally erupts from steam during its condensation.
2. Description of the Prior Art
Conversion of various forms of energy into electrical current by capitalizing on the properties of certain dielectric crystals is commonly known. Typically, a difference of electrical potential is developed across such crystals as a result of applied mechanical stresses. One type of crystal which exemplifies such properties is the well-known piezoelectric element which becomes electrically charged when it is subjected to mechanical strain.
One piezoelectric apparatus for generating electricity is shown, for example, in U.S. Pat. No. 4,442,372. As disclosed in such patent, a liquid refrigerant in a chamber is heated by a furnace until it vaporizes. The vaporized refrigerant flows through a condensing chamber and returns as a liquid to the refrigerant chamber. Upon leaving the condensing chamber, the refrigerant has condensed and its pressure has dropped. The refrigerant chamber is divided into a series of compartments by a plurality of aperture plates which successively decrease in size from the inlet to the outlet end of the condensing chamber. Passing the refrigerant successively through the staggered holes causes pressure oscillation in the elastic gas. Spring-mounted piezoelectric elements within the chamber react to the pressure variations to produce electricity.
Another generator for producing electricity by relying on the action of piezoelectric elements is disclosed in U.S. Pat. No. 4,387,318. As disclosed in the patent, piezoelectric elements are mounted in a fluid stream and made to oscillate whereby the stresses in the crystal are converted to electric current. As mentioned in the patent, water may be used as one example of the source producing the mechanical inputs.
Still another form of prior art generator for producing electricity is found in U.S. Pat. No. 3,822,388. By relying on the impulses produced by a Stirling engine, the system therein disclosed uses a fluid coupling (mercury) which transmits the power of pressure pulses generated by the engine to a load means in the form of a piezoelectric generator. A fluid coupler between the engine and the load means is shown in the form of a mercury-filled tube with a flexible diaphragm at each end to separate the mercury from the working gas of the engine and the hydraulic fluid of the generator.
The structures of U.S. Pat. Nos. 3,665,226 and 2,522,389 are respectively other examples of relying on pressure variations caused by the flexing of a diaphragm and a series of high frequency series of explosions of a suitable fuel, both to excite a transducer such as a piezoelectric element.
Although satisfactory results can be considered to develop from application of the above-exemplary prior art systems, a need exists nonetheless for a relatively simple and reliable apparatus for capitalizing on steam as the source of the mechanical stimulus exerted upon a piezoelectric device.